The Association of Perioperative Red Blood Cell Transfusions and Decreased Long-Term Survival after Cardiac Surgery
Current evidence indicates that transfusion of allogeneic RBCs during cardiac surgery is associated with increased in-hospital morbidity and mortality. Although morbidity from infections soon after the transfusion is well-known, this does not explain the decreased long-term survival rate for cardiac surgical patients. In this prospective observational study, Surgeonor and coworkers examined long-term survival for 9079 consecutive patients who received 1 or 2 RBC units during the index hospitalization for coronary artery bypass grafting (CABG) or valve surgery (or both) from 2001-2004. Mortality through June 2006 was determined and hazard ratios calculated. Complete data were available for all procedures. Of the 9079 patients 3254 (36%) were exposed to RBCs, with 56%, 43%, and 1% of transfusions given postoperatively, intraoperatively, and preoperatively, respectively. Only 27% of men compared with 63% of women received RBCs. Patients transfused were more likely to be anemic, older, smaller, female, have a depressed ejection fraction, suffer a myocardial infarction within 7 d, and have more comorbid illness. Those given a transfusion also had a greater likelihood of having a preoperative intra-aortic balloon pump and were more likely to have undergone a CABG/valve procedure. The median follow-up time was 4.4 y and the overall annual incidence rate of death was 2.7%/100 person-years. The overall crude hazard ratio (HR) for receiving blood versus no blood was 1.94. After adjusting for preoperative characteristics, RBC use led to a 16% increased hazard of death. From surgery to 6 mo postoperatively, the exposure to 1 or 2 U of RBCs was associated with a 67% increased hazard of death, whereas from 6 mo to 5 y, no significant association was found between exposure to blood and survival. These results support blood conservation and avoidance of unnecessary RBC transfusions to reduce a patient’s risk of short and long-term mortality after cardiac surgery.
